No.
The Queen is old. The number of official duties she can perform will lessen over time and Charles will essentially act as Prince Regent (though that title won't be conferred on him officially). There is however a chance she could live to be 101 like her mother (by which time it will be 2027!). Charles himself would be 79...if he is still alive. Under those circumstances he would step aside and William ( himself aged 45) would surely become the King.
Charles could end up as Prince Regent if his mother were to suffer a stroke or other serious condition that left her alive but unable to perform even the minimal set of duties expected of a British monarch.
However it also possible that Charles will pass on before Elizabeth. I think that is far likelier than Charles choosing to not reign.
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